Methyl 4-cyano-6-nitro-3-(trifluoromethoxy)pyridine-2-carboxylate
Methyl 4-cyano-2-nitro-3-(trifluoromethoxy)pyridine-5-carboxylate
Methyl 5-cyano-3-nitro-4-(trifluoromethoxy)pyridine-2-carboxylate
Methyl 6-cyano-2-nitro-4-(trifluoromethoxy)pyridine-3-carboxylate